Method of aligning interference in wireless local area network

Abstract

There is provided a method of aligning interference in a wireless local area network. A method of receiving a frame includes receiving a first frame from a first access point associated with a terminal, comparing a signal level of the first frame with a preset data rate, performing a pre-procedure for interference alignment when the signal level of the first frame is less than the preset data rate, receiving a second frame from the first access point, and aligning interference of the second frame based on information obtained through the pre-procedure. According to the present invention, it is possible to control interference in an overlapping band.

What is claimed is: 
     
       1. A method of receiving a frame that is performed in a terminal, the method comprising:
 receiving a first frame from a first access point associated with the terminal; 
 comparing a signal level of the first frame with a preset data rate; 
 performing a pre-procedure for interference alignment when the signal level of the first frame is less than the preset data rate; 
 receiving a second frame from the first access point; and 
 aligning interference of the second frame based on information obtained through the pre-procedure, 
 wherein the performing of the pre-procedure includes: 
 transmitting, to at least one neighbor access point operated in a channel overlapping an operation channel of the first access point, a probe request frame includes an indicator indicating that a frame transmission and reception procedure based on interference alignment is initiated; 
 receiving, from the at least one neighbor access point, a probe response frame including the information in response to the probe request frame; and 
 performing a procedure for estimating a channel between the first access point and the at least one neighbor access point, 
 wherein the information includes an operation channel number, bandwidth information, and a number of antennas which are supported by the at least one neighbor access point. 
 
     
     
       2. The method of  claim 1 , wherein the probe response frame is received from the at least one neighbor access point operated within a preset channel range based on an operation channel of the first access point. 
     
     
       3. The method of  claim 1 , wherein the performing of the procedure for estimating a channel includes:
 receiving a null data packet (NDP) request frame from the first access point; and 
 transmitting an NDP response frame that is a response for the NDP request frame to each of the first access point and the at least one neighbor access point. 
 
     
     
       4. A method of receiving a frame that is performed in a terminal, the method comprising:
 receiving a first frame from a first access point associated with the terminal; 
 comparing a signal level of the first frame with a preset data rate; 
 performing a pre-procedure for interference alignment when the signal level of the first frame is less than the preset data rate; 
 receiving a second frame from the first access point; and 
 aligning interference of the second frame based on information obtained through the pre-procedure, 
 wherein the performing of the pre-procedure for interference alignment includes: 
 transmitting, to at least one neighbor access point operated in channel overlapping an operation channel of the first point, a probe request frame includes an indicator indicating that a frame transmission and reception procedure based on interference alignment is initiated; 
 receiving, from the at least one neighbor access point, a probe response frame including the information in response to the probe request frame; 
 transmitting the information on at least one neighbor access point to the first access point; 
 performing a procedure for estimating a channel between the first access point and the at least one neighbor access point; and 
 announcing completion of the pre-procedure for interference alignment, 
 wherein the information includes an operation channel number, bandwidth information, and a number of antennas which are supported by the at least one neighbor access point. 
 
     
     
       5. The method of  claim 4 , wherein the performing of the procedure for estimating a channel includes:
 receiving an NDP request frame from the first access point; 
 transmitting an NDP announcement frame for announcing transmission of an NDP response frame to each of the first access point and the at least one neighbor access point; and 
 transmitting the NDP response frame to the first access point and the at least one neighbor access point. 
 
     
     
       6. The method of  claim 5 , wherein the NDP announcement frame includes identification information of each of the first access point and the at least one neighbor access point. 
     
     
       7. The method of  claim 4 , wherein the announcing of completion of the pre-procedure for interference alignment includes:
 transmitting an interference alignment (IA) request to send (RTS) frame indicating completion of the pre-procedure for interference alignment to each of the first access point and the at least one neighbor access point; and 
 receiving an IA clear to send (CTS) frame that is a response for the IA RTS frame from each of the first access point and the at least one neighbor access point. 
 
     
     
       8. A terminal, comprising:
 a processor; and 
 a memory in which at least one program command executed through the processor is stored, wherein the at least one program command causes the terminal to execute: 
 receiving a first frame from a first access point associated with the terminal; 
 comparing a signal level of the first frame with a preset minimum data rate; 
 performing a pre-procedure for interference alignment when the signal level of the first frame is less than the preset minimum data rate; 
 receiving a second frame from the first access point; and 
 aligning interference of the second frame based on information obtained through the pre-procedure, 
 wherein the performing of the pre-procedure for interference alignment includes: 
 transmitting, to at least one neighbor access point operated in a channel overlapping an operation channel of the first access point, a probe request frame includes an indicator indicating that a frame transmission and reception procedure based on interference alignment is initiated; 
 receiving, from the at least one neighbor access point, a probe response frame including the information in response to the probe request frame; and 
 performing a procedure for estimating a channel between the first access point and the at least one neighbor access point, 
 wherein the information includes an operation channel number, bandwidth information, and a number of antennas which are supported by the at least one neighbor access point. 
 
     
     
       9. The terminal of  claim 8 , wherein the performing of the procedure for estimating a channel includes:
 receiving a null data packet (NDP) request frame from the first access point; and 
 transmitting an NDP response frame that is a response for the NDP request frame to each of the first access point and the at least one neighbor access point. 
 
     
     
       10. A terminal, comprising:
 a processor; and 
 a memory in which at least one program command executed through the processor is stored, wherein the at least one program command causes the terminal to execute: 
 receiving a first frame from a first access point associated with the terminal; 
 comparing a signal level of the first frame with a preset minimum data rate; 
 performing a pre-procedure for interference alignment when the signal level of the first frame is less than the preset minimum data rate; 
 receiving a second frame from the first access point; and 
 aligning interference of the second frame based on information obtained through the pre-procedure, 
 wherein the performing of the pre-procedure for interference alignment includes: 
 transmitting, to at least one neighbor access point operated in a channel overlapping an operation channel of the first access point, a probe request frame includes an indicator indicating that a frame transmission and reception procedure based on interference alignment is initiated; 
 receiving, from the at least one neighbor access point, a probe response frame including the information in response to the probe request frame; and 
 transmitting the information on at least one neighbor access point to the first access point; 
 performing a procedure for estimating a channel between the first access point and the at least one neighbor access point; and 
 announcing completion of the pre-procedure for interference alignment, 
 wherein the information includes an operation channel number, bandwidth information, and a number of antennas which are supported by the at least one neighbor access point. 
 
     
     
       11. The terminal of  claim 10 , wherein the announcing of completion of the pre-procedure for interference alignment includes:
 transmitting an interference alignment (IA) request to send (RTS) frame indicating completion of the pre-procedure for interference alignment to each of the first access point and the at least one neighbor access point; and 
 receiving an IA clear to send (CTS) frame that is a response for the IA RTS frame from each of the first access point and the at least one neighbor access point.